1. Field of the Invention
The present invention relates to a pneumatic tire which has, on balance, an improved drainage performance, dry grip performance and wear resistance performance.
2. Description of the Related Art
As the pneumatic tire in which the dry grip performance and the drainage performance are improved, for example, there has been known a tire described in Japanese Unexamined Patent Publication No. 2004-210189. This pneumatic tire has a tread face with a tread pattern which is provided with a circumferential groove (g1) extending in a tire circumferential direction, and a plurality of oblique grooves (g2) extending from the circumferential groove (g1) toward tread edges at a comparatively small angle with respect to the tire circumferential direction as shown in FIG. 11.
In the tread pattern mentioned above, a land portion (r) is formed in a region adjacent to the circumferential groove (g1) and between the oblique grooves (g2 and g2). The land portion (r) includes an acute corner portion (c1) with an acute corner formed between the circumferential groove (g1) and one oblique groove (g2) delimiting such land portion (r), and an obtuse corner portion (c2) with an obtuse corner formed between the circumferential groove (g1) and another oblique groove (g2) delimiting such land portion (r). Such a land portion (r), however, may not exhibit a rigidity which is necessary at a time of cornering in the acute corner portion (c1). Accordingly, there is further room for improvement about an improvement of a steering stability such as a reduction of the dry grip performance and the like. Further, there is a defect that an uneven wear tends to be generated near the acute corner portion (c1).